Background

Excessive ventilation (V̇E) and abnormal gas exchange during exercise are features of chronic thromboembolic pulmonary hypertension (CTEPH). In selected CTEPH patients, balloon pulmonary angioplasty (BPA) improves symptoms and exercise capacity. How BPA affects exercise hyperventilation and gas exchange is poorly understood.

Methods

In this longitudinal observational study, symptom-limited cardiopulmonary exercise tests and carbon monoxide lung diffusion (DLCO) were performed before and after BPA (interval, mean (SD): 3.1 (2.4) months) in 36 CTEPH patients without significant cardiac and/or pulmonary comorbidities.

Results

Peak work rate improved by 20% after BPA whilst V̇E at peak did not change despite improved ventilatory efficiency (lower V̇E with respect to CO₂ output [V̇CO₂]). At the highest identical work rate pre- and post-BPA (75 (30) watts), V̇E and alveolar-arterial oxygen gradient (P(Ai-a)O₂) decreased by 17% and 19% after BPA, respectively. The physiological dead space fraction of tidal volume (VD/VT), calculated from measurements of arterial and mixed expired CO₂, decreased by 20%. In the meantime, DLCO did not change. The best correlates of P(Ai-a)O₂ measured at peak exercise were physiological VD/VT before BPA and DLCO after BPA.

Conclusions

Ventilatory efficiency, physiological VD/VT, and pulmonary gas exchange improved after BPA. The fact that DLCO did not change suggests that the pulmonary capillary blood volume and probably the true alveolar dead space were unaffected by BPA. The correlation between DLCO measured before BPA and P(Ai-a)O₂ measured after BPA suggests that DLCO may provide an easily accessible marker to predict the response to BPA in terms of pulmonary gas exchange.

中文翻译：

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慢性血栓栓塞性肺动脉高压的运动过度换气和肺气体交换：球囊肺血管成形术的效果

背景

运动期间过度通气 (V̇E) 和异常气体交换是慢性血栓栓塞性肺动脉高压 (CTEPH) 的特征。在选定的 CTEPH 患者中，球囊肺血管成形术 (BPA) 可改善症状和运动能力。BPA 如何影响运动过度换气和气体交换尚不清楚。

方法

在这项纵向观察研究中，对 36 名无明显心脏和/或心脏症状的 CTEPH 患者在 BPA 前后（间隔，平均（SD）：3.1（2.4）个月）进行了症状限制性心肺运动试验和一氧化碳肺扩散（DLCO）。肺部合并症。

结果

BPA 后峰值工作率提高了 20%，而峰值时的 V̇E 没有改变，尽管通气效率有所提高（相对于 CO ₂输出的 V̇E 较低 [V̇CO ₂ ]）。在 BPA 前后最高相同的工作速率（75 (30) 瓦）下，V̇E 和肺泡-动脉氧梯度 (P(Ai-a)O ₂ ) 在 BPA 后分别降低了 17% 和 19%。根据动脉和混合呼出 CO _{2的测量值计算得出的潮气量}生理死腔分数 (VD/VT)降低了 20%。与此同时，DLCO 没有改变。在运动高峰期测量的 P(Ai-a)O ₂的最佳相关性是BPA 之前的生理 VD/VT 和 BPA 之后的 DLCO。

结论

BPA 后通气效率、生理 VD/VT 和肺气体交换得到改善。DLCO 没有改变的事实表明，肺毛细血管血容量和可能真正的肺泡死腔不受 BPA 的影响。在 BPA 之前测量的 DLCO 和在 BPA 之后测量的 P(Ai-a)O ₂之间的相关性表明，DLCO 可以提供一个容易获得的标记来预测对 BPA 的肺气体交换反应。